1. Field of the Invention
The invention relates to a process for fabrication of a monolithic nonlinear transmission line semiconductor integrated circuit (IC). In particular, the invention discloses a novel process for fabrication of Gallium Arsenide (GaAs) varactor diodes and low parasitic capacitance lumped inductors used to interconnect the diodes in a monolithic nonlinear transmission line.
2. Description of Related Art
In a typical nonlinear transmission line, the combined and summed capacitive and inductive effect on a pulse traveling down the transmission line will decrease the transition time of the voltage step of the pulse which propagates down the line. Individually grouping or lumping discrete capacitive, resistive, and inductive components in a circuit will synthetically and electronically reproduce the same effect. Such lumped nonlinear transmission lines have been engineered and utilized to make application of the pulse shortening effect to generate very short, high-voltage pulses by all electronic means. Indeed, lumped nonlinear transmission lines are customarily used to decrease the transition time of the voltage step of a pulse which propagates down a synthetic transmission line.
Existing art nonlinear lumped transmission lines, however, exist in large part in the form of a synthesis of discrete components. Numerous attempts have been made to integrate such components into smaller and smaller packages with a characteristic impedance which is matched to the circuits to which the pulse shaping circuit is connected. Other attempts to make a single piece integrated circuit of all necessary components have been restructed to low voltage applications only. The invention disclosed herein therefore attempts to meet a long standing need for conveniently and efficiently making and manufacturing in great numbers high quality and highly efficient monolithic lumped high voltage, nonlinear transmission lines.
It will be understood that the invention process disclosed herein relates specifically to the process for fabricating a monolithic high voltage nonlinear transmission line and not the circuit design thereof. Other prior art devices have been conceived for low voltage nonlinear transmission lines for electrical pulse compression; however the novelty or the invention process disclosed herein is in the ability to fabricate a high voltage nonlinear transmission line, which by the inherent nature thereof carries a broader range of application than its lower voltage counterpart.